Karatau Mine
The Karatau Uranium Mine (Karatau) is located in the Budenovskoye uranium field in the southwestern part of the Chu-Sarysu basin in the Suzak District of the South Kazakhstan Oblast, approximately 400 kilometres northwest of Shymkent, Kazakhstan.
Karatau is an operating in situ recovery mine owned 100% by the Karatau Limited Liability Partnership, in which Uranium One has a 50% interest. The balance of the interest in Karatau is owned by Kazatomprom, the Kazakh State uranium company. Uranium One acquired its 50% interest in Karatau in December 2009.
The design capacity of Karatau is 5.2 million pounds (2,000 tonnes U) per year and it is expected that the annualized rate of production will reach this level during 2011.
Mineral Reserves and Resources
As at December 31, 2009 Karatau had the following mineral resource estimate as provided by Scott Wilson Roscoe Postle Associates Inc. ("SWRPA"):
Table 1 - Karatau Mineral Reserve Estimate
December 31, 2009
|
|
Tonnage |
Grade |
Contained U |
Contained U3O8 |
|
Probable |
6,271,000 |
0.090 |
5,640 |
14.7 |
Notes:
- Mineral reserves based on 90% wellfield recovery.
- Mineral reserves based on CIM standards.
- Figures are subject to rounding.
- Represents the portion of total reserve notionally attributable to Uranium One's 50% equity interest in the Karatau Joint Venture.
Table 2 - Karatau Mineral Resource Estimate
December 31, 2009
|
|
Tonnage |
Grade |
Contained U |
Contained U3O8 |
|
Indicated |
6,271,000 |
0.100 |
6,268 |
16.3 |
|
Inferred |
2,689,500 |
0.068 |
1,826 |
4.7 |
Notes:
- Mineral resources are based on 0.04 m% (grade x thickness) cut-off per hole and 0.10 m% per resource block.
- Indicated mineral resources include 100% of C1 resources and 50% of C2 resources.
- Mineral resources that are not mineral reserves do not have demonstrated economic viability.
- Mineral resources based on CIM standards.
- Mineral resources are inclusive of mineral reserves.
- Represents the portion of total resource notionally attributable to Uranium One's 50% equity interest in the Karatau Joint Venture.
In addition to the mineral resources estimate, SWRPA also converted part of the indicated resources to probable reserves by assuming a 90% wellfield recovery. A summary of mineral reserves is presented in Table 1.
Geology and Mineralization
The Karatau deposit is located in the Chu-Sarysu depression, which represents a large Cretaceous-age basin up to 250 km wide and which extends northward for more than 1,000 km from the foothills of the Tien Shan Mountains. The basin is an asymmetric syncline with a broad gently sloping northeast limb and an uplifted southern limb (forming the Karatau Mountains).
Overlying the basement rocks in the area of the deposit are three horizons of Cretaceous sediments that host the uranium mineralization, namely the Mynkuduk, Inkuduk and Jalpak. The depths below the surface of the three horizons are as follows:
- Mynkuduk horizon ranges from between 620 m to 800 m below the surface with an approximate thickness of 40 to 90 m;
- Inkuduk horizon occurs at a depth of between 530 m and 670 m with an approximate thickness of 105 to 130 m;
- Jalpak horizon occurs at a depth of between 470 m and 615 m below the surface with an approximate thickness of 20 to 80 m.
The Inkuduk horizon hosts the bulk of the uranium mineralization of the Karatau deposit.
Operations
Uranium is currently being extracted using in situ leaching mining methods. Sulphuric acid leaching solution is pumped into the ore zone through a network of injection wells and extracted by production wells. The well design was originally based on a 7-spot system, which employs six injection wells equally surrounding a production well. Currently the production wells are placed in rows with injection wells on the outside and production wells in the middle. The pregnant solution recovered by the production wells is then pumped to a covered settling pond and the solution is pumped into the processing plant.
A pilot production plant was constructed and commissioned at Karatau, with operations starting in December 2006. The pilot plant was contained in a single building and was serviced by separate personnel change buildings and workshops. The plant has now been expanded to commercial scale and includes a uranium refinery. The plant has sophisticated instrumentation, with both the well field and the plant being monitored and controlled using up-to-date technology. The plant has a U-tube extraction design for the removal of the uranium from solution onto ion exchange resin. The resin is then stripped with ammonium nitrate, resulting in a pregnant eluant. This eluant is refined on site and the final U3O8 product is then shipped to customers.
